Easy enough. I didn't think the torque was critical for a part like this, but thought I'd check with the experts!I doubt it is critical. Not every fastener needs to be tightened to a specific torque. The main issue is that when nylock nuts loosen by themselves, it's because the nylon is permanently deformed. Replace the nut.
It does not appear that the nut was ever tightened down in the first place! If you can run the nut down by hand all the way then the nyloc is shot, if not, snug it up and I will edit this thread later and give you the torque spec when I get home to my tech library. Look familiar? See the sensor through the hole in the center of the bearing?